Internal combustion engine cylinder head



March 10, 1942. 'I. E. ASKE 2,275,715

INTERNAL COMBUSTION ENGINE CYLINDER HEAD Filed May 15, 1941 2 Shelets-Sheet 1 Zmnent r Q IrviqgEZAs e w mum;

(Ittomeg I March 10, 1942. s 2,275,715

- INTERNAL COMBUSTION ENGINE CYLINDER HEAD Filed May 15, 1941 2 Sheets-Sheet 2 VOLUME OF CHAMBER IN PERCENT V .b

LENGTH or CHAMBER m PERCENT OIBS AV AV XIOO g x mo Ruumu [00 6 UNIT PE CENT DISTANCE XlOO '80 ROUGH RUNNlNG PERCENT VOLUME Snventor Patented Mar. 10, 1194 2" b UNlTE D j-STAT ES PATENT OFFICE INTERNAL COMBUSTION ENGINE CYLINDER HEAD E. Aske, Muskegon Heights, Mich. Application May 15, 1941, Serial No, 393,557

5 Claims.

ms or shock; and fifth, to reduce the mechanical shock on the pistons and bearings, thereby increasing the wear life ,of th engine.

I'attain the aforesaid objects and others that will be apparent from a perusal of the descripchamber portion [5 to the short extended portion'G, Spark plug I6, by suitable electric current, provides the electric jump spark for igniting the fuel charge compressed within the comtion when taken in connection with the accompanying drawings, in which: n

Figure 1 is a. sectional view of my cylinder head taken ona line I--I of Figure 2, hereinafter described.

Figure 2 is an under or cylinder closing'face plan view of the cylinder head illustrating my perferred arrangement of the combustion chamber and parts pertaining thereto.

bustion chamber, and having opening into said clsiamber products of combustion exhaust valve Numeral ll illustrates the upper portion of a cylinder block of the engine closed by cylinder head body I, except for the opening I 8 between the combustion chamber 4 and the cylinder bore I. A sealing gasket l 5 is placed between the head body I and the cylinder block l1. Suitable bolts passing through holes attach the cylinder head body securely to the cylinder block, and

holes 2| provide for circulation of cooling fluid between the cylinder block and head, and 22 represents the position of the point of ignition.

Referring to Figure 3 which represents the 'bogeyOABCDEFG established from an analysis of the combustion volume distribution of com- I bustionrchambers used in most present engines. From measurements taken of vibration noise and the relative harshness of internal combustion engines operation having various arrangements of volume distribution, it became possible to erect Figure 3 is a chart showing in the upper portion, by curves, the percentage of total volume for any given percentage of the total distance from the'point of ignition, and in the lower portion their respective curves that show the ratios of the percentage volumes removed to the corref spending percentage radial distances. The totalvolume represents the total compressed volume in the combustion chamber, and the total distanceis the maximum spherical radius distance taken from the point of ignition to the outer boundary wall I as shown in Figure 2 of the combustion chamber portion over the cylinder bore.

Throughout the several views comprising the drawings, similar numerals refer to similar parts and referring thereto:

Numeral i represents the cylinder head body portion having formed therein 'a cooling fluid chamber 2, a cylinder closing face 3, in which is depressed combustion chamber 4 having a long extended portion 5 and a shorter extended portion 6, joined over the cylinder bore 1 designated by broken line 9 by curved wall I, the portion ll of the combustion chamber boundary wall extends in an irregular curve I! from its juncture with the wall of the long extension 5 to around the spark plug position [3, and joins the curve wall H extending around the exhaust valve a chart of my improved combustion chamber performance bogey, which extends beyond the bogey OAFG, Patent No. 2,138,131, by the area ABCDEFA. Inmy experiments it was discovered that when the ignition took place in a larger volume of fuel surroundingit, giving the'ordinate HP, the power was greater than when the vol ume was smaller, having the ordinate HK. Near the end of complete combustion, representing about 72% of the length of the combustion chamber, it was found advantageous to have a larger volume of fuel to burn, which is shown byordinate MN than the smaller volume MR. By carefully proportioning the initial end the end volumes of the chamber so as to produce peaks- .well within the area ABCDEFA, more power and better economy results than when they are reduced to come within the bogey OABC of my said Patent No. 2,138,131. v n

From further study, it was found that when the maximum incremental volume to incremental distance ratio took place within 49% of the maximum radius distance S from ignition point 22 of Figure 3, there was a substantial improvement over a chamber having the same maximum value occurring at a greater distance from the ignition point. Graphs LPNJ and TWZ serve to illustrate the differences in combustion chamber characteristics between a smooth and rough running engine.

Each of the aforesaid combustion chambers having the same volume, but dlfl'er in their re:-

, spective maximum radius distances, position of I the ignition point, and volumetric arrangement considered from said ignition point, therefore any chamber graphically analyzed for volume distribution that :has maximum values coming within the area ABCDEFA will be most satis- -factory for engine operation smoothness and high economy. A high peak in the graph during the first 40% of distance is an advantage over a lower value, so long as the limits of the bogey is limited to the farthest extremity of the combustion chamber from the point of ignition.

The ordinate referred to is laid out from zero to two-hundred and represents the ratios of .incremental volumes to the corresponding incremental distances multplied by one-hundred, and is based upon one-hundred percent volume and one-hundred percent distance.

From the respective ratios obtained by analyz- Q ing two different combustion chambers for volume distribution by my method, herein described, the graphs LPJ and TWZ were constructed.

The percent of total volume for each volume increment V divided by the corresponding percent of total radius distance increment S, multiplied by one-hundred, establishes the respective points of the graphs LPJ and TWZ.

The graphs L'J' and T'Z' represents the perpercent of the maximum radius distance.

centage of volume-V contained in the chamber for any given percentage distance S of the chamber taken from the point of ignition. As an example, at 40% distance the chamber contains 34% of the total volume for graph LJ'. For.

graph T2 the percentvolume is 17.

The graph LPJ also indicates thespace rate of change of incremental volumes consumed at constant pressure, as the inflammation wave spreads, through to the outermost limits of the chamberas shown in the lower part of Figure 3. The ordinate HP taken at the point of maximum value, representing 40% of the total radial distance ofgthe chamber, corresponds to the'ratio 183. Thisvalue indicates that the volume at that pointis increasing 1.83 times as fast as the lineal radial distance for the same interval S,

which represents about 3 /z% of the total radius distance.

The distance from the ignition point 22, to the outermost limit or boundary of the chamber is designated by line S in Figure 2, and fixed at 100% of the spherical radius distance in the chart of Figure 3. The increment S of the graphs corresponds to the interval S of Figures 1 and 2, where S represents a lineal radial distance or increment swept through by the flame as it travelsforward on the spherical radius S. During the distance S a volume V is consumed. Symbol V represents 100% of total volume of the chamber, gasket clearance, and piston clearance when the piston is at the top of its stroke of The area enclosed by the boundary lines passing through the pointsABCDEFA, is my bogey within which the maximum incremental volume .to distance ratios will substantially occur for all combustion chambers coming within the scope of my invention. The abscissas and ordinates of points ABCDEFA are designated respectively by the figures (22%, 148), (30%, 200), (40%, 200),

The shape and amplitude of the curve LPNJ depends upon the position of the ignition point relative to the distribution of volume of the com- As there are a large number bogey, and give satisfactorily smooth operation of the engine. To facilitate the work of analyzing a combus tion chamber for volume distribution, I employ a plaster of Paris cast made of the shape of the entire interior of the combustion chamber, including the gasket and piston clearance volume. The ignition point is carefully located on the cast, and the cast is mounted upon a turntable machine designed for the purpose of sweeping out or removing definite spherical portions of the plaster, preferably one-eighth inch in width at given radial distances from the ignition point to simulate the shape of the combustion wave front. The spherical shaped portions thus removed, which come out in the form of powder, closely represent the progress of the flame wave front as it travels through the chamber. The weight of these powdered portions represent relatively exact volume proportions of the fuel mixture that are.burned when compared to the total weight of the cast. These incremental portions are expressed in percent of the total weight ,of the cast, and the incremental distance as the Thus it is quite simple to cut up the cast into a large number of small increments and construct the graphs LJ, T'Z', and their corresponding graphs LPNJ, TWZ.

Tofurther illustrate the progress of the com-. bustion wave front through the combustion chamber volume, refer to Figure 3. Combustion starts at the ignition spark, between the terminals of the spark plug, preferably located in the deepest portion of the combustion chamber above the valve area, and it spreads in a supposedly concentrically spherical wave front consumingcombustibles in proportion to the volumes swept through from the ignition spark to the curved wall l0, and into the farthest extended portions 5 and 6 of the combustion chamber,- then through the passage l8 into the clearance space l8 between the piston and face 3 of the cover.. The area of the passage I8 is considerably greater than the area of the fuel inlet valve opening which is not shown but is a counterpart, to the exhaust valve 10' which is substantially closed at the start of ignition and throughout duration of combustion. When the combustion wave reaches the extended portion 5, the outermost boundary point of the chamber, all combustibles of the fuel'will have sudden, blow-like impulse. of highly accelerated dermis chambers where combustible volumes are improperly or haphazardly arranged in relation to the progress of the wave front from the point of ignition.

Referring to the subject matter of my Patent No. 2,138,131, issued November 29; 1938, the ignition point was so located with respect to the combustion volume so as to greatlylimit the amount of fuel burned during the early stage of combustion. The effect of that limitation was to unduly retard the generation of pressure. In my present invention, the ignition point is so located in relation to the combustible volume that a A much larger portion of the volume is burned dur-' ing the early stage of combustion, the effect of the increase in initial combustion, combined with a smaller increase near the later end, is to imfuel portion, the piston head, connecting rod, crankshaft and bearings, which all actas sudden and blow-like impulsesthat give rise to mechanical vibration and engine roughness in adtil - rapid will become the pressure increase and the greater will be the magnitude of the applied and restoring forces.

prove engine smoothness of operation, increase its power output, and lessen thetendency of the engine to detonate under low octane rated fuel.

In carrying out my presentinvention and to obtain these named objects, it is necessary to set forth certain geometrical relations applying to the shape and volume of the engine's combustion chamber, and location of the spark plug whereby one skilledln the art can accurately design a combustion chamber to more closely approach the ideal form without having to resort to the usual cut and try methods at present em- 1 ployed, which involve great expense by necessarily having to conduct many operative .tests on an engine and which, in most cases, form no base for comparisons from which accurate conclusions can be drawn for establishing a working standard in designing combustion chambers. In my present invention it is only necesary to apply the fundamental facts concerning combustion of the fuel that have been established by scientific investigation, to wit: that the ignition spark ignites only that portion of the fuel mixture in which it is closely surrounded, that the initial ignition ignites succeeding zones of radially adjacent fuel, and thereby produces a flame wave that spreads from the point of ignition throughout the fuel mixture until all combustibles therein are ignited and burned; that the velocity of the combustion process is substantially rapid in all directions from the point of ignition, and consequently forms a spherical wave front emanating from said point; that the volume contained in the wave front equals that of the incremental portions of fuel mixture it encounters at its respective distance from the point of ignition, and that the volume of the incremental portions consumed at the wave front are determined by the volume and shape of the combustion chamber as related to-the point of ignition; that the pressures developed at any stage of the combustion flame front are closely proportional to the ratio of-the incremental fuel mass consumed at the wave front to that of the entire mass offuel to be burned when thep'iston is at the starting of the power stroke. Hence, pro-determination of the reaction or rebound forces against the unburned The magnitude of pressure change in pounds 7 per square inch per second provides a comparative measure for judging the vibration roughness of the engines operation, as its effects in producing vibration are far more pronounced than the maximum pressure developed in pounds per square inch from the entire'explosion-like combustion to the fuel. For illustration, if a pressure ofone-hundred pounds per square inch uniformly increases to one-hundred and fifty pounds per square inch in one thousandth of a second, the rate of change of pressure would be fifty thousand pounds per square inch per second. Therefore the accelerating force necessary to establish the above rate of change of pressure would be fifty million pounds per square inch per second persecond, since the acceleration is the rate of the velocity change for a unit of time. If the growth of this pressure was limited to onehalf the former amount, by restricting the consumption of fuel to one-half its former amount, the rate of change of pressure and accelerating force would be reduced by one-half of their former values. When the rate of pressure change and acceleration forces are multiplied by the piston area they become very large, and create rough and noisy operation and possible damage to the engine parts.

It should be understood that it is not only necessary to limit the rate of change of pressure to low values, but to properly position the occurrence in thecombustion cycle, as what might be thought a low value of combustible volume during the early stageof combustion could become a high value at a later stage of combustion,

In the past and at present, designs of combus-' tion chambers reflected the skill of the designer, his judgment and ability to provide maximum power output of the engine and economy thereof through choice of mechanical details, and until recently very little attention has been given to the importance of fuel volume distribution in combustion chambers and its effects 'upon the performance of the engine. And, where 'these factors have been considered of importance. no working pattern or bogey has been established by geometrical considerations other than dis-' closed by my Patent No. 2,138,131, that would give the designers of engines a definite guide in laying out combustion chambers for producing smoothness in engine operation throughout all sizes of engines, and their compression ratios.

While I have described my invention quite fully and outlined a method for its accomplishment, I desire it to be understood that the invention is not to be-limited .to the particular illustrative disclosure, and that the scope of my present invention and the rights thereto, I desire to secure are set-forth in the claims hereafter enumerated:

1. In an internal combustion engine including a cylinder block having a plane top face, a cylinder bore extending into the said block from the said face, a piston in the said bore and adapted to be reciprocated therein, and a cylinder head having a plane face for engaging the plane top face of the cylinder block and closing the cylinder bore therein; a combustion chamber extending into the cylinder head from its plane face, and having extending therein a spark plug including a pair of electrodes having theirpoint of ignition within the combustionchambe'r, the said combustion chamber having concentrically spherical volumes so related to the said ignition point of the electrodes, total combustion volume and total radial distance from said point that the maximum ratio of any increment of combustion volume to the total volume, multiplied by one hundred, and divided by the corresponding ratio of incremental radius to the total radius distance, will come within the limits 0, B, C, D, E, G, of the chart shown in Figure 3 of the drawings.

2. In an internal combustion engine including a, cylinder block having a. plane top face, a cylinder bore extending into the said block from the said face, a piston in the said bore and adapted to be reciprocated therein and a cylinder head having a plane face for engaging the plane top face of the cylinder block and closing the cylinder bore therein;v a combustion chamber e'xtending into the cylinder head from its plane face,

tance, will come within the limits A, B, C, D, E,

F, of the chart shown in Figure 3 of the drawings.

3. In an internal combustion engine including a cylinder block having a plane top face, a cylinder bore extending into the said block from the said face, a piston in the said bore and adapted to be reciprocated therein and a cylinder head having a plane face for engaging the plane top face of the cylinder block and closing the cylinder bore therein; a combustion chamber extending into the cylinder head from its plane face, and having extending therein a spark plug including the electrodes having their ends located within the combustion chamber, the said combustion chamber having concentrically spherical volumes so related to the point of location of the said electrodes, total combustion volume and total radial distance from said space that the maximum ratio of any increment of combustion volume to the total volume, multiplied by one hundred, and divided by the corresponding ratio of incremental radius to the total radius distance, will come within the limits of the area enclosed by the lines A to B, B to Q0 toD, D to E, E to F, and F to A, of the bogey shown in Figure 3 of the drawings.

4. In a cylinder head for internal combustion engines, the said cylinder head having a cylinder closing face with a combustion chamber extending into the head from the said cylinder closing face, the said combustion chamber having an ignition point located therein .and concentrically spherical volumes so related to the said ignition point, total combustion volume and total radius distance from the said ignition point thatthe maximum ratio of any radial increment of combustion volume to the total volume, multiplied by one hundred, and divided by the corresponding ratio of incremental radius to the total radius distance, shall come within the vertical limits 200%, 200%, 140%, 120%, and 40%, at the corresponding respective horizontal radius distances 10%, 20%, 30%, 34%, 40%, 45%, and

corresponding ratio of one-eighth inch incremen-- tal radius to the total radius distance, shall come closely within the limits of the area enclosed by the lines extending from A to B, B to C, C to D,

.D to E, E to F, and F to A of the bogey shown in Figure 3.

, IRVING E. ASKE. I 

